An estimated 3,000 gig-goers gathered at the Ohio Dreams venue in Butler for the EST 2016 event on Saturday (06Aug16), when a man began passing out the packets of colourful sweets to the crowd.

The packages were marked "prescribed medibles", according to reports, and were laced with high levels of Tetrahydrocannabinol (THC), the same drug found in marijuana.

Authorities reveal 24 people were hospitalised after eating the free candies, but were released after being treated with overdose antidote naloxone.

"They didn't lose consciousness. They just felt different," Major Joe Masi of the Richland County Sheriff's Department told the Mansfield News Journal.

Police identified the suspect as 28-year-old Michigan man Matthew L. Gross, who was subsequently arrested and charged with trafficking in drugs, according to the local paper.